Powdered polyurethane urea resin composition for slush molding and manufacturing process therefor

A method for producing the powdery polyurethane urea resin composition for slush molding comprising a polyurethane urea resin (D) whose total content of a dicondensate of acetone, a dicondensate of methyl ethyl ketone, and a dicondensate of methyl isobutyl ketone is 1,000 ppm or less, and an additive (N), wherein the polyurethane urea resin (D) has formed thermoplastic polyurethane urea resin particles (P) having irregularities on the surface thereof and having a shape factor SF1 of from 101 to 200, a shape factor SF2 of from 120 to 240, and a volume-average particle diameter of from 20 to 500 μm, the method comprising the following step 1 and the following step 2-1 or step 2-2:

• step 1:
• the step of producing polyurethane urea resin fine particles (G) having a volume-average particle diameter of 0.1 to 60 μm comprising the-polyurethane urea resin (D) whose total content of a dicondensate of acetone, a dicondensate of methyl ethyl ketone, and a dicondensate of methyl isobutyl ketone is 1,000 ppm or less;
• step 2-1:
• the step of obtaining thermoplastic polyurethane urea resin particles (P) having irregularities on the surfaces thereof by causing coalescence of the polyurethane urea resin fine particles (G) by heating the (G) to a temperature of from [the thermally softening temperature of the (D)−10]° C. to [the thermally softening temperature of the (D)+10]° C. under stirring at a peripheral speed of 0.5 to 50 m/s;
• step 2-2:
• the step of obtaining thermoplastic polyurethane urea resin particles (P) having irregularities on the surfaces thereof by causing coalescence of the (G) by heating the (G) to a temperature of from 70° C. to [the thermally softening temperature of the (D)+10]° C. under stirring at a peripheral speed of 0.5 to 50 m/s in the presence of 5 to 30% by weight, based on the weight of the (G), of an organic solvent (T) having a solubility parameter differing by 3 or less from that of the polyurethane urea resin (D);
• wherein the additive (N) is added and mixed in any of the step 1, or the step 2-1 or step 2-2, or the step of obtaining a raw material of the (D) before the step 1, or the step after obtaining the resin particles (P),
• wherein the polyurethane urea resin (D) is a polyurethane urea resin obtained by a production method comprising the step of mixing and stirring a mixture of an alicyclic diamine and/or an aliphatic diamine (B) and an aqueous solution (L) containing a surfactant, or water with an isocyanate group-terminated urethane prepolymer (A),
• wherein the prepolymer (A) is formed from an aliphatic diisocyanate (a1) and an active hydrogen component comprising a monool (a2), a high molecular diol (a3) having a number-average molecular weight of from 500 to 10,000 and an active hydrogen-containing compound represented by formula (1):
• wherein, in formula (1),
• R1 represents a monovalent group formed by removing one active hydrogen atom from a monovalent or polyvalent active hydrogen-containing compound, or a hydroxy group;
• and when there are a plurality of R1s, the R1s each may be the same or different;
• R2 represents a divalent group formed by removing two active hydrogen atoms from a divalent active hydrogen-containing compound, and when there are a plurality of R2s, the R2s each may be the same or different;
• Y represents a tri- or more valent group formed by removing all carboxyl groups from a tri- or more basic aromatic polycarboxylic acid;
• the aromatic ring of Y is constituted from carbon atoms, wherein a substituent may be attached to any of the carbon atoms, and at least one of the carbon atoms has thereon no substituents attached thereto;
• each substituent on the aromatic ring of Y, when present, is independently an alkyl group, a vinyl group, an allyl group, an amino group, or a halogen atom;
• a represents an integer of 1 or greater,
• b represents an integer of 0 or greater, and 3≦a+b≦d−1 is satisfied, where d represents the number of hydrogen atoms bound to the carbon atoms constituting the aromatic ring in the event that all substituents including the carboxyl groups of the aromatic polycarboxylic acid have been substituted with hydrogen atoms, that is, the number of the sites that can be substituted on the aromatic ring.

A method for producing the powdery polyurethane urea resin composition for slush molding comprising a polyurethane urea resin (D) whose total content of a dicondensate of acetone, a dicondensate of methyl ethyl ketone, and a dicondensate of methyl isobutyl ketone is 1,000 ppm or less, and an additive (N), wherein the polyurethane urea resin (D) has formed thermoplastic polyurethane urea resin particles (P) having irregularities on the surface thereof and having a shape factor SF1 of from 101 to 200, a shape factor SF2 of from 120 to 240, and a volume-average particle diameter of from 20 to 500 μm, the method comprising the following step 3 and step 4:

• step 3:
• the step of producing polyurethane urea resin fine particles (G) having a volume-average particle diameter of 0.1 to 60 μm comprising the polyurethane urea resin (D) whose total content of a dicondensate of acetone, a dicondensate of methyl ethyl ketone, and a dicondensate of methyl isobutyl ketone is 1,000 ppm or less, and then producing a slurry (R) comprising the (G) and an aqueous solution (L) containing a surfactant, or water;
• step 4:
• the step of obtaining thermoplastic polyurethane urea resin particles (P) having irregularities on the surface thereof by causing coalescence of the polyurethane urea resin fine particles (G) by adding an organic solvent (T) having a solubility parameter differing by 3 or less from that of the polyurethane urea resin (D) to the slurry (R) and then stirring at a temperature of 10° C. or higher at a peripheral speed of 0.1 to 10 m/s;
• wherein the additive (N) is added and mixed in any of the step 3 or the step 4, or the step of obtaining a raw material of the (D) before the step 3, or a step after obtaining the resin particles (P),
• wherein the polyurethane urea resin (D) is a polyurethane urea resin obtained by a production method comprising the step of mixing and stirring a mixture of an alicyclic diamine and/or an aliphatic diamine (B) and an aqueous solution (L) containing a surfactant, or water with an isocyanate group-terminated urethane prepolymer (A),
• wherein the prepolymer (A) is formed from an aliphatic diisocyanate (a1) and an active hydrogen component comprising a monool (a2), a high molecular diol (a3) having a number-average molecular weight of from 500 to 10,000 and an active hydrogen-containing compound represented by formula (1):
• wherein, in formula (1),
• R1 represents a monovalent group formed by removing one active hydrogen atom from a monovalent or polyvalent active hydrogen-containing compound, or a hydroxy group;
• and when there are a plurality of R1s, the R1s each may be the same or different;
• R2 represents a divalent group formed by removing two active hydrogen atoms from a divalent active hydrogen-containing compound, and when there are a plurality of R2s, the R2s each may be the same or different;
• Y represents a tri- or more valent group formed by removing all carboxyl groups from a tri- or more the aromatic ring of Y is constituted from carbon atoms, wherein a substituent, may be attached to any of the carbon atoms, and at least one of the carbon atoms has thereon no substituents attached thereto;
• each substituent on the aromatic ring of Y, when present, is independently an alkyl group, a vinyl group, an allyl group, an amino group, or a halogen atom;
• a represents an integer of 1 or greater,
• b represents an integer of 0 or greater, and 3≦a+b≦d−1 is satisfied, where d represents the number of hydrogen atoms bound to the carbon atoms constituting the aromatic ring in the event that all substituents including the carboxyl groups of the aromatic polycarboxylic acid have been substituted with hydrogen atoms, that is, the number of the sites that can be substituted on the aromatic ring.